Simplify the following expression: $n = \dfrac{5z}{6} - \dfrac{z}{4}$
Explanation: In order to subtract expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $6$ and $4$ $\lcm(6, 4) = 12$ $ n = \dfrac{2}{2} \cdot \dfrac{5z}{6} - \dfrac{3}{3} \cdot \dfrac{z}{4} $ $n = \dfrac{10z}{12} - \dfrac{3z}{12}$ $n = \dfrac{10z -3z}{12}$ $n = \dfrac{7z}{12}$